The Cellular Immunology and Fluids Core (CIF) Core will support the HNRC's mission by maintaining the Center's valuable inventory of cells and body fluids and providing scientific leadership on the role of cellular immune processes in neuroAIDS. The Core will assure meticulous stewardship of the store of cells and fluids by 1) providing a secure, centralized, continuously monitored storage system; 2) maintaining an advanced BSL level 2/3 laboratory for processing of biohazardous samples; 3) retrieving samples and arranging for prompt transfer to HNRC investigators and their collaborators; and 4) maintaining an accurate inventory that incorporates quality control and feedback systems. Samples within the store are tracked by innovative, real-time, high-capacity Sybase software on a web-based server. This system allow personal to directly scan bar-coded labels that encode specific identifiers for participant, visit, date, and aliquot location. Thus, accurate inventories and efficient use of freezer space are facilitated. Stored samples are available for neuroAIDS-focused studies following a formal approval process. To advance our understanding of the role of cellular immunology in neuroAIDS, the Core will assist studies that investigate 1) the role of peripheral T-cell immune responses; 2) the role of mutant forms of beta chemokine receptors and their ligands in CSF; 3) the relationship between the cytokine expression profiles exhibited by PBMCs and brain-derived cells; and 4) the relationship between pathogen-specific T-cell responses and opportunistic infections of the brain. In this manner the Core will serve as a repository for cell and fluid samples essential to realizing the Center's mission of supporting innovative research, enhancing productivity, and facilitating rapid programs in neuroAIDS.